Designation: A 632 – 01 An American National Standard

Standard Specification forSeamless and Welded Austenitic Stainless Steel Tubing(Small-Diameter) for General Service 1

This standard is issued under the fixed designation A 632; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This specification covers grades of stainless steel tubingin sizes under1⁄2 down to 0.050 in. (12.7 to 1.27 mm) in outsidediameter and wall thicknesses less than 0.065 in. down to 0.005in. (1.65 to 0.13 mm) for general corrosion-resisting and low-or high-temperature service, as designated in Table 1.

NOTE 1—The grades of austenitic stainless steel tubing furnished inaccordance with this specification have been found suitable for low-temperature service down to −325°F (−200°C) in which Charpy notched-bar impact values of 15 ft·lbf (20 J), minimum, are required and thesegrades need not be impact tested.

1.2 Optional supplementary requirements are provided and,when desired, shall be so stated in the order.

1.3 The values stated in inch-pound units are to be regardedas the standard.

2. Referenced Documents

2.1 ASTM Standards:A 262 Practices for Detecting Susceptibility to Intergranu-

lar Attack in Austenitic Stainless Steels2

A 370 Test Methods and Definitions for Mechanical Testingof Steel Products3

A 751 Test Methods, Practices, and Terminology forChemical Analysis of Steel Products3

A 941 Terminology Relating to Steel, Stainless Steel, Re-lated Alloys, and Ferroalloys4

E 165 Test Method for Liquid Penetrant Examination5

E 527 Practice for Numbering Metals and Alloys (UNS)4

2.2 SAE Standard:SAE J 1086 Practice for Numbering Metals and Alloys

(UNS)6

3. Terminology

3.1 Definitions—For definitions of terms used in this speci-fication, refer to Terminology A 941.

4. Ordering Information

4.1 Orders for material under this specification shouldinclude the following, as required, to describe the desiredmaterial adequately:

4.1.1 Quantity (feet or number of lengths),4.1.2 Name of material (seamless or welded tubes),4.1.3 Grade (see Table 1),4.1.4 Size (only two of the following: outside diameter,

inside diameter, and average wall),4.1.5 Length (specific or random),4.1.6 Optional requirements (check analysis, see Section 15;

hydrostatic or nondestructive electric test, see Section 16),4.1.7 Test report required,4.1.8 Specification designation, and4.1.9 Special requirements or any supplementary require-

ments selected, or both.

5. Manufacture

5.1 Manufacture—The tubes shall be cold finished and shallbe made by the seamless or welded process.

5.2 Heat Treatment—All material shall be furnished in theheat-treated condition. The heat-treatment procedure shallconsist of heating the material to a minimum temperature of1800°F (980°C) and quenching in water or rapidly cooling byother means.

6. Chemical Composition

6.1 The steel shall conform to the requirements as tochemical composition as specified in Table 1.

7. Product Analysis

7.1 When specified on the purchase order, an analysis ofeither one billet or one length of flat-rolled stock or one tubeshall be made from each heat. Samples for chemical analysis,except spectrochemical analysis, shall be taken in accordancewith Test Methods A 751. The chemical composition thusdetermined shall conform to the requirements specified.

7.2 If the analysis made in accordance with 7.1 does notconform to the requirements specified, an analysis of each

1 This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel, and Related Alloys, and is the direct responsibility of SubcommitteeA01.10 on Stainless and Alloy Steel Tubular Products.

Current edition approved May 10, 2001. Published June 2001. Originallypublished as A 632 – 69. Last previous edition A 632 – 98.

2 Annual Book of ASTM Standards,Vol 01.03.3 Annual Book of ASTM Standards,Vols 01.01, 01.02, 01.03, 01.04, and 01.05.4 Annual Book of ASTM Standards,Vol 01.01.5 Annual Book of ASTM Standards,Vol 03.03.6 Available from Society of Automotive Engineers, 400 Commonwealth Drive,

Warrendale, PA 15096.

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Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.

billet or length of flat-rolled stock or tube from the same heatmay be made and all billets, stock, or tubes thus conforming tothe requirements shall be accepted so far as chemical compo-sition is concerned.

8. Mechanical Properties

8.1 Tensile Requirements—The material shall conform tothe requirements as to tensile properties specified in Table 2.These mechanical properties apply to tubing1⁄8 in. (3.2 mm)and larger in outside diameter by 0.015 in. (0.38 mm) in wallthickness and heavier. Smaller sizes are available meeting theminimum tensile strength specified in Table 2; however, yieldstrength is not generally determined on such sizes, and theminimum elongation shall be 25 %.

9. Permissible Variations in Dimensions

9.1 Variations in diameter and wall thickness from thosespecified shall not exceed the amounts specified in Table 3.

10. Surface Condition

10.1 The tubes shall be pickled free of scale. When brightannealing is used, pickling is not required.

11. Number of Tests

11.1 For each lot of 100 finished tubes or fraction thereof,two tubes shall be selected at random for the flaring test (seeNote 2).

11.2 One tension test shall be made on a specimen for lotsof not more than 50 tubes. Tension tests shall be made onspecimens from two tubes for lots of more than 50 tubes (seeNote 3).

NOTE 2—For flaring requirements, the termlot applies to all tubes ofthe same nominal size and wall thickness that are produced from the sameheat of steel and subjected to the same finishing treatment in a continuousfurnace; when final heat treatment is in a batch-type furnace, the lot shallinclude only those tubes that are heat treated in the same furnace charge.

NOTE 3—For tensile requirements, the termlot applies to all tubes priorto cutting, of the same nominal diameter and wall thickness that areproduced from the same heat of steel. When final heat treatment is in abatch-type furnace, a lot shall include only those tubes of the same sizeand the same heat that are heat treated in the same furnace charge. Whenthe final heat treatment is in a continuous furnace, a lot shall include alltubes of the same size and heat, heat treated in the same furnace at thesame temperature, time at heat and furnace speed.

11.3 When more than one heat is involved, the test require-ments prescribed in 15.1 shall apply to each heat.

11.4 Each tube shall be subjected to a pressure test or thenondestructive test described in Section 16.

12. Retests

12.1 If the results of tension or flaring tests do not conformto the specified requirements, retests may be made on addi-tional tubes of double the original number from the same lot,each of which shall conform to the specified requirements.

12.2 If any tension test specimen shows defective machin-ing or develops flaws, it may be discarded and anotherspecimen substituted. If the elongation of any tension testspecimen is less than that specified, and any part of the fractureis more than3⁄4 in. (19.0 mm) from the center of the gage

TABLE 1 Chemical Requirements

Element

Composition, %

Grade TP 304 TP 304L TP 310 TP 316 TP 316L TP 317 TP 321 TP 347 TP 348

UNSDesignationA S30400 S30403 S31000 S31600 S31603 S31700 S32100 S34700 S34800

Carbon, max 0.08 0.030 0.15 0.08 0.030 0.08 0.08 0.08 0.08Manganese max 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00Phosphorus, max 0.045 0.045 0.045 0.045 0.045 0.045 0.045 0.045 0.045Sulfur, max 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.030Silicon, max 0.75 0.75 0.75 0.75 0.75B 0.75 0.75 0.75 0.75Nickel 8.0–11.0 8.0–13.0 19.0–22.0 11.0–14.0C 10.0–15.0 11.0–14.0 9.0–13.0 9.0–13.0 9.0–13.0Chromium 18.0–20.0 18.0–20.0 24.0–26.0 16.0–18.0 16.0–18.0 18.0–20.0 17.0–20.0 17.0–20.0 17.0–20.0Molybdenum ... ... ... 2.00–3.00 2.00–3.00 3.00–4.00 ... ... ...Titanium ... ... ... ... ... ... D ... ...Columbium + tantalum ... ... ... ... ... ... ... E E

Tantalum, max ... ... ... ... ... ... ... ... 0.10A New designation established in accordance with Practice E 527 and SAE J 1086, Practice for Numbering Metals and Alloys (UNS).B For seamless TP316L tubes, the silicon maximum shall be 1.00 %.C For welded TP 316 tubes, the nickel range shall be 10.0–14.0 %.D Grade TP 321 shall have a titanium content of not less than five times the carbon content and not more than 0.60 %.E Grades TP 347 and TP 348 shall have a columbium plus tantalum content of not less than ten times the carbon content and not more than 1.0 %.

TABLE 2 Tensile Requirements

Tensile strength, min, ksi (MPa) 75A (515)A

Yield strength, min, ksi (MPa) 30A,B (205)A,B

Elongation in 2 in. or 50 mm, min, % 35B

A Grades TP 304L and TP 316L shall have a minimum tensile strength of 70 ksi(485 MPa) and a minimum yield strength of 25 ksi (170 MPa).

B Yield strength is not generally determined on tubing sizes smaller than 1⁄8 in.(3.2 mm) in outside diameter or thinner than 0.015 in. (0.38 mm) wall, so yieldstrength is not required on such sizes. Also, the minimum elongation required onthese smaller or thinner sizes is 25 %.

TABLE 3 Permissible Variations in Dimensions

Outside Diameter RangeOutside

Diameter,in. (mm)

InsideDiameter,in. (mm)

Wall,plusand

minus, %

Up to, but not including 3⁄32

(0.094) in. (2.38 mm)+0.002 (0.05)−0.000

+0.000−0.002 (0.05)

10

3⁄32 (0.094) in. (2.38 mm) but

not including 3⁄16(0.188)in. (4.76 mm)

+0.003 (0.08)−0.000

+0.000−0.003 (0.08)

10

3⁄16 to, but not including, 1⁄2(0.500) in. (12.70 mm)

+0.004 (0.10)−0.000

+0.000−0.004 (0.10)

10

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length as indicated by scribe scratches marked on the specimenbefore testing, a retest shall be allowed.

13. Retreatment

13.1 If the tubes selected to represent any lot fail to conformto the test requirements, the lot represented may be retreatedand resubmitted for test.

14. Test Specimens and Test Methods

14.1 Test specimens shall be taken from the ends of thefinished tubes before being cut to length. They shall be smoothon the ends and free of burrs and flaws and properly identifiedwith the lot from which they are taken.

14.2 Specimens shall be tested at room temperature.14.3 The specimens and mechanical tests required shall be

made in accordance with Supplement II of Test Methods andDefinitions A 370.

15. Manipulation Test

15.1 Flaring Test—A section of tube approximately 4 in.(101.6 mm) in length shall stand being flared with a tool havinga 60° included angle until the tube at the mouth of the flare hasbeen expanded to the following percentages without crackingor showing flaws:

Ratio of Inside Diameterto Outside Diameter

Minimum Expansion ofInside Diameter, %

0.9 210.8 220.7 250.6 300.5 390.4 510.3 68

NOTE 4—These flare tests shall not be required on sizes under 0.093 in.(2.38 mm) in inside diameter.

16. Hydrostatic or Nondestructive Electric Test

16.1 Each tube shall be subjected to the nondestructiveelectric test or the hydrostatic test. The type of test to be usedshall be at the option of the manufacturer, unless otherwisespecified in the purchase order.

16.2 Hydrostatic test:Each tube at the final size shall be hydrostatically pressure

tested or air pressure tested under water.16.3 Tubes that are hydrostatically pressure tested shall

have the hydrostatic test pressure determined by the followingequation, but shall not exceed 1000 psi (6.89 MPa):

P = 2St/D

where:P = hydrostatic test pressure, psi or MPa,S = allowable fiber stress of 16 000 psi (110.3 MPa),t = specified wall thickness, in. or mm, andD = specified outside diameter, in. or mm.

16.4 The air-pressure test under water shall be performed at500-psi (3.4-MPa) pressure or at a pressure equivalent to amaximum fiber stress of 16 000 psi (110.3 MPa) by theequation shown above, whichever is less.

16.5 The test pressure shall be held for a minimum of 5 s.16.6 If any tube shows leaks during the hydrostatic test or

the air pressure test, it shall be rejected.16.7 Nondestructive Electric Test:16.8 Each tube shall be tested at the mill by passing it

through a nondestructive tester capable of detecting defectswith a depth exceeding 10 % of the wall thickness or 0.002 in.(0.05 mm), whichever is greater. Testing will not be requiredon sizes under 0.125 in. (3.18 mm) in outside diameter.However, at the option of the purchaser, tubing to be drawn toa diameter under 0.125 in. may be tested while in the rangefrom 0.156 in. (3.97 mm) to 0.125 in. outside diameter, and anydefects that are found shall be culled out before any furtherreductions are made.

17. Inspection

17.1 The inspector representing the purchaser shall haveentry, at all times while work on the contract of the purchaseris being performed, to all parts of the manufacturer’s plant thatconcern the inspection of the material ordered. The manufac-turer shall afford the inspector, without charge, all reasonablefacilities to satisfy the inspector that the material is beingfurnished in accordance with this specification. All tests andinspections shall be made at the place of manufacture prior toshipment, unless otherwise specified, and shall be so conductedas not to interfere unnecessarily with the operation of the plant.

18. Rejection

18.1 When inspection at the place of manufacture has beenwaived by the purchaser, any rejection shall be reported to themanufacturer within 30 working days from receipt of samplesby the purchaser.

19. Certification

19.1 When inspection at the place of manufacture has beenwaived by the purchaser, the manufacturer shall furnish, onrequest, a statement that the material has been tested and hasmet all requirements of this specification.

20. Product Marking

20.1 The name or brand of the manufacturer, the grade ofthe material from which the tube is made (such as Type 304),the letters ASTM, and the specification designation shall bemarked on a tag securely attached to the bundle or box inwhich the tubes are shipped.

21. Keywords

21.1 austenitic stainless steel; seamless tube; small diam-eter; stainless steel tube; steel tube; welded steel tube

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SUPPLEMENTARY REQUIREMENTS

The following supplementary requirements shall apply only when specified by the purchaser in theinquiry, contract, or order.

S1. Dye Penetrant Inspection

S1.1 Each tube shall be submitted to a visible dye orfluorescent dye penetrant examination. The procedure for thisspecification shall conform to Test Method E 165. The typepenetrant and the acceptance level shall be agreed uponbetween the purchaser and manufacturer.

S2. Embrittlement Test

S2.1 Tubing shall be capable of meeting the intergranularcorrosion test specified in Practice E of Practices A 262 in theas-shipped condition. Stabilized and low-carbon grades shallbe capable of meeting the requirements of this test in thesensitized condition (1 h at 1240°F [675°C]).

S3. Cleanliness

S3.1 The tubing shall be suppliedthermocouple cleanonthe inside surface.Thermocouple cleanis defined as being freeof all drawing compounds, carbon, dirt, dust, and othercontaminants. A test for this degree of cleanliness is made by

passing a swatch of lint-free yarn or cloth, or felt plug, soakedin alcohol or acetone through the tube. A light discoloration ofthe swatch is not a cause for rejection unless it containsparticles of grit or metallic flakes (no magnification used). Inaddition, freedom from inside surface oxide shall be deter-mined by sectioning, pickling, and washing short lengths oftubing and comparing with the tubing in the original untestedcondition. After cleaning, the tubing shall be capped orotherwise protected to ensure cleanliness upon arrival at itsdestination.

S4. Unstraightened Tubes

S4.1 When the purchaser specifies tubes unstraightenedafter final heat treatment (such as coils), the minimum yieldstrength of Table 2 shall be reduced by 5 ksi.

S4.2 On the certification, and wherever the grade designa-tion for unstraightened tubing appears, it shall be identifiedwith the suffix letterU (for example, 304-U, 321-U, and soforth.).

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connectionwith any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any suchpatent rights, and the risk of infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make yourviews known to the ASTM Committee on Standards, at the address shown below.

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